Aprotinin: is it prothrombotic?

Controversy continues as to whether aprotinin (Trasylol) is prothrombotic. The recent discovery of the thrombin receptor family, known as the protease -activated receptor family (PAR) has been essential in aiding our understan ding of the mechanism of action of aprotinin. Our results show that aprotin in has no effect on platelet aggregation induced by adrenaline, adenosine d iphosphate, phorbol-12-myristate-13-acetate, collagen or PAR 1 agonist pept ide. However, aprotinin inhibits thrombin-induced platelet activation as as sessed by macroaggregation, microaggregation and platelet membrane calcium flux, Aprotinin inhibits proteolytic activation of platelets, but platelets can still be activated by non-proteolytic mechanisms.